1. Field of the Invention
The invention relates to an audio system comprising an audio interface. The invention further relates to an audio interface for use in such an audio system.
2. Description of the Related Art
Audio systems and audio interfaces are known in the art. For example, such interfaces are used with CD-players, DAT and MD recorders, etc. In a consumer implementation, the quality is, in most cases, restricted to 16-bit linear PCT format, with a sample rate of 32, 44.1 or 48 kHz. However, the latest consumer electronics products can perform at a higher quality, for example, by using 24-bit samples or a sample rate of 88.2, 176.4 or 192 kHz. The present digital audio interface specification can be used for 24-bit samples, however, not for higher sample rate frequencies.
Further, the protection of the rights of the author and supplier of a copyright protected work is a main concern of the suppliers of such work. Due to the digital revolution, making a (almost) perfect copy is becoming very easy. As a consequence, no copyright is paid. The suppliers ask regularly for technical measures to restrict the possibilities of copying and, preferably, to make copying impossible.
It is, inter alia, an object of the invention to provide an audio system and an audio interface that overcomes the drawbacks of the prior art.
To this end, a first aspect of the invention provides an audio system comprising a sender device, an audio interface and a receiver device, whereby the sender device is arranged to receive a first audio signal from an audio source, converting means for converting the first audio signal into a second audio signal, and to supply the second audio signal via the audio interface to the receiver device, and the receiver device is arranged to receive the second audio signal, converting means for converting the second audio signal into a third audio signal, and supply the third audio signal to an audio destination, characterized in that the audio interface comprises a bi-directional bus for sending control signals between the sender device and the receiver device.
A second aspect of the invention provides an audio interface for use in such an audio system.
A third aspect of the invention provides a receiver device for use in such an audio system.
By using a bi-directional control bus, it is made possible to amend the audio signal in the sender device, to make it suitable for the receiver device. Further, in this way, it is made possible to let the receiver device first make a request of allowance to receive high quality audio and, after allowance, to receive it.
When no request is made, the sender device will send, for example, the normal audio quality.
It is mentioned here that European Patent Application No. EP-A-0542345, corresponding to U.S. Pat. No. 5,313,524 (PHN 13,883), discloses an active sound reproducer and control unit which uses a bi-directional control bus as a control channel to supply remote control commands.
In an embodiment of an audio system, according to the invention, the sender device comprises a control unit for sending and receiving the control signals to a control unit of the receiver device.
With both the sender device and the receiver device having a control unit, the control signals will be supplied and received by the respective control unit. The control units further can control the audio signal quality to be sent and to be received.
In an embodiment of an audio interface, according to the invention, a first part of the audio interface is incorporated in the sender device and a second part of the audio interface is incorporated in the receiver device.
By splitting the audio interface into a sender and a receiver part, the devices themselves are all to communicate with the other.